Novel 3-D helix-flexible nerve guide conduits repair nerve defects.

Flexible nerve guide conduits (NGCs) are desired in peripheral nerve reconstruction near the joints. Inspired by the engineered structure of the helical tube, we addressed the problems of conventional NGCs often mentioned in clinical feedback. We developed a type of helix-flexible NGC (HF-NGC) and evaluated its mechanical properties as well as its flexibility, and it performed excellently during in vitro tests. During the in vivo tests, HF-NGCs and conventional nonflexible NGCs (NF-NGCs) were implanted in a rat sciatic nerve defect model. A short-term investigation showed that Schwan cells (SCs) infiltrated into the helical groove, and most of them belonged to the activated SC type. Compared with NF-NGCs, HF-NGCs had fewer apoptotic SCs. In the long term investigation, HF-NGCs maintained flexibility in vivo after 3 months. Analyses of the morphometric parameters of nerve fibers and the static sciatic index showed that the HF-NGCs had similar regeneration outcomes to those of traditional NF-NGCs. Therefore, this style of HF-NGC could be used to repair peripheral nerve damage in a cross-joint region with less tension during operation and easy to postoperative rehabilitation. We believe that the HF-NGC is a potentially valuable candidate for clinical use.